When mysterious clouds began to form over Cape Town, South Africa, people reacted—not by panicking in the streets, but by pulling up Instagram. The so-called "UFO Clouds," which get their name from their flying saucer shape, are known as "lenticular clouds." While they're rare, they're not unheard of, and they sure make for beautiful snapshots. According to National Geographic, lenticular clouds are formed when "strong, moist winds blow over rough terrain." Considering that Cape Town has some pretty impressive examples of rough terrain, like

This isn't the first time that lenticular clouds have appeared in the world—or on social media. In 2013, photos of the alien clouds were captured over Mt. Hood in Oregon. There have also been dramatic cloud formations in Scotland and over Mt. Fuji in Japan.